Abstract

For six artificial glasses, for Solenhofen limestone, and for Vinal Haven diabase, the compressibility has been measured to a pressure of 10,000 kg/cm2, combined with temperatures of from 0° to 300° or 400° C. For all these materials, except silica glass, the compressibility is found to increase with the temperature above about 200°, although in a number of cases the behavior below this temperature is more or less complicated. The values observed for the diabase are notably lower than any hereto‐fore recorded for similar rocks; estimates are given of the velocity of seismic waves in this diabase at different depths, down to 40 kilometers.